Patent GB-687295-A (GB)
Title: Process for converting polymers into powdered form and the powdered products so produced
IPC: B29B9/00
Filed: 1950-06-20
Abstract: Heat-reactive polymeric esters prepared from unsaturated alcohols having at least one ethylenic linkage not more than four carbon atoms removed from a hydroxyl group, and polycarboxylic acids in powder form are produced by spraying into a hot, dry, inert gas, e.g. air, carbon dioxide, nitrogen or helium, a solution of a polymer-monomer mixture (at least 90 per cent polymer) in solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diamyl ketone. Catalysts, e.g. hydrogen, benzoyl, lauryl, acetyl, benzoylacetyl, di-t-butyl and amyl, monochloro- and dichloro-di-t-butyl, and t-butyl t-amyl peroxides, t-butyl and cumene hydroperoxides, t-butyl perbenzoate, peracetate and perpelargonate, and t-butyl ethyl percarbonate, 2,2-bis-(t-butyl peroxy) butane or propane or mixtures thereof; dyes, stabilizers and plasticizers may be added before spraying by a gun or rotary spinner in a drum from which the powder is separated by a cyclone separator.  The esters may be prepared from alcohols such as allyl, methallyl, ethallyl, chlorallyl alcohols, 2- and 3-buten-1-ol, 4-chloro-3-buten-1-ol, 2-penten-1-ol, 2- and 4-hexen-1-ol, 5 - cyclohexyl - 3 - hexen - 1 - ol, 3 - methyl - 2,4-hexadiene - 1 - ol, 3 - cyclohexyl - 2 - propen - 1 - ol, 2-isopropyl-2-propen-1-ol, 2-isopropyl-2-buten-1-ol, 2-phenyl-2-buten-1-ol, 3-acetoxy-2-propen-1-ol, 4-bromo-2-hexen-1-ol, 3-ethyl-2-penten-1-ol, and 2-octen-1-ol and acids such as malonic, succinic, glutaric, adipic, suberic, sebacic, glutaconic, maleic, fumaric, a -b -dibutyl succinic, a -ethyl glutaric, 2-octenedioic, 2,5-heptadienedioic, 1,1,5-pentane- and 1,2,4-hexane tricarboxylic, tricarballylic, phthalic, iso- and terephthalic, hemi- and tri-mellitic, mellophanic, di- and tetra - chlorophthalic, dibromoterephthalic, and 2-nitrophthalic, naphthalene dicarboxylic, and dimethyl phthalic acids; specified are diallyl, dimethallyl, and vinyl allyl phthalates, triallyl trimellitate, dichloroallyl succinate, divinyl adipate, 2-butenyl allyl malonate, allyl crotyl sebacate, methallyl allyl tetrachlorophthalate and diethallyl isophthalate. They may be polymerized alone or in admixture or copolymerized with styrene, vinyl, vinylidene and allyl halides, vinyl esters of saturated monocarboxylic acids, methyl acrylate and methacrylates, vinyl, allyl and methallyl esters of phosphoric acid and orthoacids of silicon and boron, conjugated butadiene, chlorobutadiene, isoprene, pentadienes, hexadiene, and diallyl diglycollate.  The required polymer-monomer ratio is obtained by interrupting the polymerization before the gel stage by discontinuing the heating or destroying the catalyst, e.g. hydrogen, sodium, barium, benzoyl, di-t-butyl, tetraline, olefin, acetyl and acetone peroxides, the alkali metal perborates and persulphates, and t-butyl hydroperoxide by reducing agents, and extracting the monomer with solvents such as methyl, isopropyl, butyl and amyl alcohols, dodecanols, ethyl, isopropyl and butyl ethers, hexanes, heptanes and octanes.  In examples, powdered polymeric diallyl phthalate, dimethallyl phthalate, diethallyl tetrachlorophthalate, and di-2-butenyl sebacate are produced and may be used as solutions in solvents, e.g. acetone or diallyl phthalate or monomeric unsaturated esters, to form varnishes, laminates or impregnating solutions, or mixed with catalysts, lubricants, dyes, wood flour, a -cellulose and asbestos to give moulding powders.